Jennifer Lopez: 'You Have to Follow Your Heart'

Jennifer Lopez has many things: perma-radiance, Pucci dresses, lots and lots of Louboutins and a $250 million empire. But she's also a 43-year-old single mom trying to learn from her mistakes.

"I'm not a young girl anymore who can throw caution to the wind," says the mega-star, who is settled into a sofa, picking at a small bowl of sweet potato and corn mash after a daylong PEOPLE photo shoot.

By her side is Casper Smart, 25, her live-in boyfriend. But while the choreographer – whom she calls by his given name, Beau – makes Lopez very happy, she's quick to point out that after her split from Marc Anthony, the father of her 4-year-old twins, Max and Emme, she's not rushing things.

"I'm making decisions for three. . . . I'm Mama Bear," says Lopez. "I want to make sure everything's right. I have been hasty in the past. Super hasty."

Then again, this is not a woman who is afraid of big change. Last year the mogul who topped Forbes's Celebrity 100 List walked away from a multi-million-dollar gig judging American Idol.

Now – after a world tour with Smart by her side – she's applying her laser focus to reigniting her film career. In Parker, a heist movie costarring Jason Statham, Lopez tackles the kind of gritty part that evokes acclaimed roles like the one she played in 1998's Out of Sight.

"She came in with no airs and just mucked in like everyone else," says Statham. "Jennifer walked away from a lot of money on American Idol," adds director Taylor Hackford. "She said, 'You know what? This [acting] is what I want to do right now.' " Lopez identified with her character, a woman picking up the pieces after her divorce.

"At this point in my life, I lived enough to do great work," says Lopez. "I've really felt everything by now."